90 METALLURGY OP IRON AND STEEL. Holley* on the work of a Board appointed by the United States Government to test material for chain cables. It was found that the tenacity of 2-inch bars for chain cables should be from 48,000 to TABLE III-C. Wrought-Iron Plates from Shear and Universal Mills. Sheared Plates. , , Universal Mill Plates. IB O> rt S H I -4 d £ & to ft u cf <r •§ 01 n> 01 1ii)'2 n S 5* <M 01 S fi« d ?> 2& B •H Thickness ii Number of 1 eraged. Elastic limi square inc Ultimate st HJs.persqu Elongation per cent. Reduction o per cent. Number of eraged. Elastic limi square inc Ultimate st fts. per squ Elongation per cent. Reduction o percent. iv 1 82400 51800 11.2 18.9 1 82100 51000 13.0 19.0 H? 2 81050 50650 14.6 21.8 73 5 81180 49760 14.2 22.0 8 • 81100 50580 17.8 26.2 S8 4 80775 50200 15.5 22.5 8 80500 50880 17.2 24.9 % 2 80400 49050 16.0 22.4 8 81470 52570 19.0 26.2 5S_,000 pounds per square inch, while 1-inch bars should show 53,000 to 57,000 pounds. This conclusion illustrates the profound influence of reduction in rolling. The slag varied from 0.192 per cent, to 2.262 per cent, of the total weight of the iron. Some makers may have supposed that slag would facilitate welding, but the investigation did not bear this out, for it is distinctly stated that, while "slag should theoretically improve welding, like any flux, its effect in these experiments could not be definitely traced." On the contrary, the iron highest in slag (2.26 per cent.) "welded less soundly than any other bar'of the same iron, and below average as compared with the other irons." The percentage of slag not only varied in different brands of iron, but in pieces of the same make. This was true also of all the factors investigated. Table III-D shows the variations in the same make of iron, two extreme cases being given under each head. It also gives the maximum and minimum individual records. SEC. Illg.—Conditions affecting the welding properties.—Conditions of varying work, percentages of slag, and irregularity of the same irons, not to mention the possible overheating of piles, com- * The Strength of Wrought-Iron as Affected by its Composition and by its Reduction in Rolling. Trans.A. I. M. E., Vol. YI, p. 101.